Barcode systems are used in a variety of applications for record keeping, article tracking and control. Typically an article has an imprinted barcode which includes identity data. The barcode is deciphered by a barcode reader revealing the identity of the object and permitting analysis and control based upon this data.
Such barcode tracking and control systems are of value in tracking and control of people. A typical use would be in attendance tracking and job analysis of employees using barcode imprinted employee badges. Another use would be in ticket taking.
Several problems exist in the prior art which prevent more widespread use of barcode reader systems in badge and ticket applications. Current barcode readers which are inexpensive enough for widespread use in these applications are insufficiently capable of reliable use by first time users.
Barcode readers come in manual scanning and self-scanning types. Manual scanning barcode readers include swipe types and wand types. Swipe type readers require the user to manually move the element including the imprinted barcode through a sensing region, which is generally a slot. Wand type readers require manual movement of a sensing element over the imprinted barcode. Self-scanning barcode readers include laser scanners and charge coupled device (CCD) scanners.
There are two common problems inherent in most existing swipe type readers. The first problem with swipe type readers is that the barcode must be on the correct side of the card (i.e., facing the single scanner opening in one side of the slot). The second problem is that the card must be swiped smoothly through the slot within a limited speed range. There is a substantial chance of misreading the barcode or of being unable to read the barcode if the swipe is not smooth or is not within the limited speed range. Even if the swipe is within the limited speed range, the barcode reader may not always read correctly if the barcode is not of high quality.
Wand type readers have problems similar to swipe type readers. Wand type readers are more likely to be scanned on the proper side in the first instance than swipe type readers because the user can see the relationship between the sensor and the barcode when using the wand. In other respects wand type readers are even worse than swipe type readers. Wand type readers require considerable technique to be reliable. They tend to be rather sensitive to the speed and smoothness of the motion of wanding the card. There is no inherent guide for the motion of wanding the barcode as provided in swipe type readers. In addition, wand type readers are inherently more vulnerable to abuse and misuse than swipe type readers due to the exposed components in the wand.
Self-scanning barcode readers are more likely to provide reliable first readings. Laser scanners generally employ moving mirrors for scanning. Laser scanners have a large depth of field and are thus useful in applications where the position of the barcode is not fixed. Laser scanners typically provide more reliable readings than manual scanning barcode readers, but are expensive and have moving parts which can break down. Laser scanners are typically not employed in card or badge readers because of their expense. However if laser scanners were so employed, most would also require the card or badge to be inserted facing the correct way. Charge coupled device scanners are very reliable, have high read rates for poor barcodes, and are less expensive than laser scanners. Thus charge coupled device scanners would be nearly ideal for these applications, but currently available configurations still require the badge or ticket to face the correct way to read.
Our prior U.S. patent application Ser. No. 07/463,112 filed Jan. 11, 1990, entitled BARCODE BADGE AND TICKET READER disclosed a system employing a charge coupled device type scanner in conjunction with an illumination source, a set of mirrors and a card guide. Light from the illumination source is directed to both sides of the card. The scanning field of the charge coupled device is split in two, with the mirrors directing the split field to opposite sides of the card guide. This enables the badge or ticket to be inserted with the barcode on either side and still be readable. The split of the scanning field of the charge coupled device requires that the length of the charge coupled device be twice the length of the barcode.
The system of our prior patent application also has problems. This system requires a single charge coupled device scanner to cover either side of the card. As a consequence either the charge coupled device must be twice as long as the barcode scanned or some resolution is lost.
Therefore there is a need in the art for a barcode reader which is both cost effective and which provides a high probably of a correct first reading when employed by naive users. It would be particularly ideal to have such a barcode reader for badges or tickets which does not require a particular orientation for correct reading.